Your right – we don’t actually know the policy of the shul in question. But four very valid possibilities leads one to remember to be ?? ??? ???? – there could be endless possible reasons, and we’ve guessed four without thinking too much. I could probably come up with a couple more if I would spend the time thinking.
So what started off as a complaint against the ‘achdus of klal yisroel’ actually sounds perfectly legitimate. Of course, the ‘victim’ can’t see it like that, because when you are in the story, you understandably that you are wronged. But when somebody with an outside view without the blurred perspective of a person involved looks, you realize that it actually makes quite a bit of sense.
Not judging is a very important policy.